Bluetooth: Remove unnecessary 'send' parameter from smp_failure()

The send parameter has only been used for determining whether to send a
Pairing Failed PDU or not. However, the function can equally well use
the already existing reason parameter to make this choice and send the
PDU whenever a non-zero value was passed.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>